Hunt Chat - springfield stalker musket question

Hi, I recently aquired a CVA made springfield stalker musket, does anyone know anything about these guns? it appears to be made approximately circa 1970s? it has a number eleven nipple on it which i would have thought would have used a musket cap it has a large springfield hammer, i contacted Harrington and richardson which appears to be a defunct company i contacted marlin and hand r 1871 company, nothing, i can only find one on the web on a list of confiscated guns in a new zealand police website, other than that nothing, i would like to know when it was made, what a good load is, and whether i can use a musket cap nipple on it, i forgot to mention although an almost identical clone to the springfield musket, it is 45 caliber! i didnt know if that meant it had to use a number eleven cap, any help is appreciated, vtbowhunter..:)